A panoramic photo of the lunar surface captured by China’s Chang’e 5 as it landed on the Moon in 2020. Credit: China National Space Administration
China’s Chang’e 5 lander returned to Earth on 16 December 2020 with the first sample brought back from the Moon since 1976. Within the roughly 1.7 kg sample, researchers found a glass bead with a pit about 9 µm across, formed by the impact of a piece of fast-traveling space dust known as a micrometeorite. On the rim of the tiny crater they found two titanium-based minerals—trigonal and triclinic Ti2O—that had not been found on the Moon before and do not occur naturally on Earth. Those are now the seventh and eighth new minerals discovered on the Moon to date, as described in a recent Nature Astronomy paper by Xiaojia Zeng, Yanxue Wu, and colleagues.
Above Earth, the friction generated by meteors moving through the atmosphere slows them down and can burn them up, depending on their incoming size and speed. Above the Moon and other airless bodies, though, there is no atmospheric buffer between the debris of space and the rocky surface. The Moon is thus bombarded not only with the large meteors and asteroids that have given rise to its iconic cratered surface but also with tiny dust-sized meteors that travel at high speeds—as fast as 20 km/s, about 30 times as fast as an F-16 jet. Those micrometeorite impacts are crucial to the weathering of the lunar surface. READ MORE...
